title: Guide RNA-binding complex from mitochondria of trypanosomatids.
abstract: In the mitochondria of trypanosomatids, the majority of mRNAs undergo massive uracil-insertion/deletion editing. Throughout the processes of pre-mRNA polyadenylation, guide RNA (gRNA) uridylylation and annealing to mRNA, and editing reactions, several multiprotein complexes must engage in transient interactions to produce a template for protein synthesis. Here, we report the identification of a protein complex essential for gRNA stability. The gRNA-binding complex (GRBC) interacts with gRNA processing, editing, and polyadenylation machineries and with the mitochondrial edited mRNA stability (MERS1) factor. RNAi knockdown of the core subunits, GRBC1 and GRBC2, led to the elimination of gRNAs, thus inhibiting mRNA editing. Inhibition of MERS1 expression selectively abrogated edited mRNAs. Homologous proteins unique to the order of Kinetoplastida, GRBC1 and GRBC2, form a stable 200 kDa particle that directly binds gRNAs. Systematic analysis of RNA-mediated and RNA-independent interactions involving the GRBC and MERS1 suggests a unified model for RNA processing in the kinetoplast mitochondria.
authors.affiliation: Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, Irvine, CA 92697, USA.
authors.forename: James
authors.initials: J
authors.lastname: Weng
authors.forename: Inna
authors.initials: I
authors.lastname: Aphasizheva
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Etheridge
authors.forename: Lan
authors.initials: L
authors.lastname: Huang
authors.forename: Xiaorong
authors.initials: X
authors.lastname: Wang
authors.forename: Arnold M
authors.initials: AM
authors.lastname: Falick
authors.forename: Ruslan
authors.initials: R
authors.lastname: Aphasizhev
mesh_terms: D000818:Animals; D007891:Leishmania / Q000235:genetics*; D008928:Mitochondria / Q000378:metabolism*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D026723:Polyadenylation; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D017393:RNA Editing / Q000502:physiology; D034622:RNA Interference; D012322:RNA Precursors / Q000378:metabolism; D020871:RNA Stability; D017394:RNA, Guide, Kinetoplastida / Q000378:metabolism* / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D046912:Multiprotein Complexes; D021122:Protein Subunits; D015800:Protozoan Proteins; D012322:RNA Precursors; D012333:RNA, Messenger; D017394:RNA, Guide, Kinetoplastida